Cold-cathode stepping tube



Oct. 11, 1960 Filed July 18, 1958 G. O. CROWTHER COLD-CATHODE STEPPINGTUBE 4 Sheets-Sheet 1 INVENTOR. GEMLD OFFLEY Czeownzm AGEN T Oct. 11,1960 G. o. CROWTHER 2,956,205

' COLD-CATHODE STEPPING TUBE Filed July 18, 195a 4 Sheets-Sheet 2INVENTOR GERALD OFFLEY CROWTHER BY MA- AGENT Oct. 11, 1960 G. o.CROWTHER 2,956,205

COLD-CATHODE STEPPING TUBE Filed July 18, 1958 4 Sheets-Sheet 3 INVENTORGERALD 0F F LE Y GROWTH! R AGENT Oct. 11, 1960 s. o. CROWTHER 2,956,205

COLD-CATHODE STEPPING TUBE Filed July 18, 1958 4 Sheets-Sheet 4 FIG;8

lNV ENTOR GERALD OFFLE Y CROWTHER BY M E.

AGENT United States Patent COLD-CATHODE STEPPING TUBE Gerald OflleyCrowther, Cheam, England, assignor to North American Philips Company,Inc., New York, N.Y.

Filed July 18, 1958, Ser. No. 749,461

Claims priority, application Great Britain July 26, 1957 4 Claims. (Cl.SIS-84.6)

This invention relates to neon discharge counting tubes having a centralanode and a plurality of rod-shaped main cathodes symmetricallysurrounding the anode, with between every two main cathodes two likewiserod-shaped auxiliary electrodes, which bring about transfer of thedischarge from one main cathode to a succeeding main cathode, theauxiliary electrodes being connected in parallel as two rows.

In US. patent application Serial No. 723,404, filed March 24, 1958, nowUS. Patent No. 2,905,860, issued September 22, 1959, it has already beensuggested to displace one of the main cathodes, viz. the zero or markingcathode, with respect to the other electrodes, so that the voltagedifference between the anode and the marking cathode which is necessaryfor transfer of the discharge to this cathode is higher than for theother cathodes. Consequently, upon transfer of the discharge to themarking cathode, it is possible to derive from the tube a higher voltagepulse sufiicient for direct control of a tube connected in cascade tothe first tube.

It has been found that if, on the one hand, the condition must befulfilled that the biassing potential to be applied to the markingcathode in the circuit is not very critical and, on the other hand, thatthe transfer from the marking cathode via the auxiliary electrodes tothe succeeding main cathode should take place with security, thestructure according to the prior application is not always satisfactory.

An object of the invention is to provide a construction which is notvery critical in regard of the biassing potential of the marking cathodeand in which the discharge from the marking cathode may be displacedWithout difiiculty.

According to the invention, in a neon discharge counting tube having acentrally-arranged anode and a plurality of nod-shaped main cathodessymmetrically surrounding the anode, with between every two maincathodes two likewise rod-shaped auxiliary electrodes, which bring abouttransfer of the discharge from one main cathode to a succeeding maincathode, which auxiliary electrodes are connected in parallel as tworows, part of the zero or marking cathode is displaced with respect tothe other electrodes so that the voltage difference between the anodeand said part of the marking cathode which is required for transfer of,the discharge to said part is higher than for the other cathodes, whilethe ratio of the distances between said part of the marking cathode andthe preceding first and second auxiliary electrodes is substantially thesame as for the other cathodes, the marking cathode having a second partwhich is also displaced outwards, but which is at the same distance fromthe succeeding first auxiliary electrode as are the other main cathodes.

It has been found that the above-mentioned ratio must satisfy thespecified conditions, because otherwise the on the arcuated dot-and-dashline r.

biassing potential of the marking cathode becomes too critical for thecircuits normally applied, while the second part of the marking cathodemust be sufficiently close to the succeeding first auxiliary electrodeto permit a certain transfer to this auxiliary electrode.

The invention will now he described with reference to the accompanyingdrawing, in which:

Figs. la, 1b and 1c are, respectively, a plan view, a sectional viewtaken along the line II-II, and a diagrammatic view of an electrodestructure for a tube according to the invention;

Fig. 2 is a diagrammatic view of an electrode structure according to theinvention.

Figs. 3, 4 and 5 are plan views of a plurality of electrode arrangementsaccording to the invention, of which Figs. 6, 7 and 8 are theside-views.

Fig. 1 shows a portion of the electrode arrangement of a decade countingtube. S is a ceramic disc in which the cathodes and auxiliary electrodesare fixed. The anode (not shown) is a disc parallel to the plane ofdrawing having a diameter a little less than corresponding to thepositioning of the electrodes in the disc S. Of the electrodes there areshown the main cathode K9, the associated first auxiliary electrode GA9and the second auxiliary electrode GB9. The cathode K0 is positionedoutside the curved line on which the other electrodes are situated.Normally, the electrode K0 would have to occupy the position indicatedby X. The position of electrode K0 is chosen so that the ratio of thedistances d1 and 112 to the first and second preceding auxiliaryelectrodes is substantially the same as f the electrode would haveoccupied the position indicated by x.

In order to bring about with security a transfer from K0 to GAO, theelectrode K0 would have to be situated Fig. 2 shows the position ofelectrode K0 if this condition were fulfilled for the electrode K0displaced outwards.

However, if will be evident that, in the case of Fig 2, the ratiobetween d1 and d2 approaches unity much more than in the case of Fig. 1.This results in the biassing potential to be applied to K0 beingcritical.

Figs. 3 and 6 show how the electrode K0 is composed of two parallel rods1 and 2 which are united by welding at 8 by means of the bent portion 7of Fig. 6.

In Figs. 4 and 7, the electrode K0 comprises an L-like rod having limbs3 and 4 such that the discharge passes via GA9 and GB9 to the point of 3and can pass from the bend between 3 and 4 to GAO.

In Figs. 5 and 8, the electrode K0 comprises a rod 6 having a plate 5welded thereto.

What is claimed is:

1. A glow discharge tube comprising an anode, a plurality of rod-shapedmain cathodes symmetrically disposed about and surrounding the anode, aplurality of rod-shaped auxiliary electrodes spaced from and betweenadjacent main cathodes to effect a transfer of the discharge from onecathode to an adjoining cathode, said auxiliary electrodes beingconnected in two parallel rows, and a rod shaped marker cathode having afirst portion for the transfer of the discharge thereto positionedrelative to the auxiliary electrodes at which the potential differencebetween the anode and the portion of the marker cathode required fortransferring the discharge thereto is higher than for the othercathodes, the ratio of the distances between said portion of the markingcathode and the next preceding auxiliary electrodes being substantiallythe same as for the other cathodes, said marker cathode having a secondportion similarly positioned and being at substan Patented Oct. 11, 1960tially the same distance from the next succeeding auxiliary 4. A glowdischarge tube as claimed in claim 1 in which electrode as are the othermain cathodes. the marker cathode comprises a rod having a platelike 2.A glow discharge tube as claimed in claim 1 in which Portion Securedtheretothe marker cathode com rises two arallel s aced rods joinedtogether by a bent iaortion of ne of the rods. 5 References Clted 1n thefile of thls Patent 3. A glow discharge tube as claimed in claim 1 inwhich UNITED STATES PATENTS the marker cathode is L-shaped. 2,739,266Burnett Mar. 20, 1956

